The recent availability of microprocessors opens up great new potential in biomedical engineering for a new class of instrumentation. Complex data processing and control tasks may now be performed in individual instruments, while, at the same time, simplifying man-machine interaction. Effective application of microprocessor technology to clinical instrumentation requires a critical mass of expertise and higher-level languages is beyond the means and capability of most clinical engineering groups. A Center is proposed which assembles the required medical and engineering expertise and technology to employ effectively the power of microprocessors in solution of important clinical instrumentation problems. The Center will consist of a Core Microprocessor Engineering Laboratory, to be located on the M.I.T. campus, and several project sites at Harvard teaching hospitals. Effective interaction among engineers and physicians is assured through organization and staffing of all research projects on an interdisciplinary collaborative basis.